AskScience AMA Series: I'm Here to Talk About Roots and Shoots: How Plants Prosper in the Desert and What it Means for Agriculture and Biodiversity, AMA!

Submitted by AskScienceModerator t3_zwe2th in askscience

I am Shimon Rachmilevitch, a plant ecophysiologist at the Institute for Agriculture and Biotechnology within the Blaustein Institutes for Desert Research at Ben Gurion University of the Negev since 2007. I completed my B.Sc. in Biology, and then continued to complete my M.Sc. and Ph.D. in plant sciences, all degrees at the Hebrew University of Jerusalem. I carried out post-doctoral research at University of California Davis and Rutgers University and spent three years as a visiting professor at Harvard and Cornell universities. I published over 100 peer reviewed studies and supervised over 50 students and post docs from all over the world, of which most have continued either in academic or industrial research.

The overall goal of my research is to explore adaptation and acclimation mechanisms of plants to the desert environment in both natural and agricultural vegetation. Understanding tolerance mechanisms of plants grown in desert environments is invaluable for increasing the genetic pool of tolerant plants for agriculture and for maintaining biodiversity in natural ecosystems. A focus of this research is the root system and the interaction between roots and shoots that enable plants to prosper in drylands. The lab takes advantage of its location in the desert and studies the surrounding natural and agricultural ecosystems. I collaborate with many researchers and receive research grants from different foundations, including the Israeli Science Foundation, BARD, and Ministry of Agriculture. In the last six years I managed the "Root of the Matter" knowledge center. I also collaborate with the agritech industry including Baier, Evogene, Netafim and Syngenta. I serve as the head of the Israeli Society for Plant Sciences and the Mirilashvili Center for Food Security in the Desert, and am the chair of the DDD - Desert, Dryland and Desertification international conference in collaboration with the UN, which in its last conference, hosted over 800 scientists from more than 50 different countries.

You are welcome to learn more about my lab: https://rachmilevitchlab.weebly.com/

I will be on at 10am PST (1 PM EST, 18 UT), Ask Me Anything!

Usernames: /u/israelinsf

1,254

Comments

You must log in or register to comment.

Sea_sharp t1_j1u802n wrote

Do the desert plants you've studied have mycorrhiza in their roots?

30

IsraelinSF t1_j1vcexf wrote

Most plants have mycorrhizae as well as bacteria. The whole area around the roots including the roots is the rhizosphere. There is ectomycorhiza and endomycorhiza. It changes depending on species and abiotic and biotic conditions.

16

Randombleizinthewild t1_j1uchwl wrote

Hi !

  1. How are Plants used to prevent the desert to increase?

  2. For example, in the case of the gobi desert, only native plants are used or do you sometimes add other plants?

  3. If we add a lot of plants in a place in the desert, is it possible to alter the climate? And bring more rain in a place?

25

IsraelinSF t1_j1vd7a4 wrote

Plants can be used to prevent desertification. The Great Green Wall in the Sahara is an example, which was an initiative by the UN and the UNCCD (UN Convention for Combatting Desertification). Plants stabilise the soil, fertilise the soil, and can allow for other plants to grow by changing the climate and soil conditions, including the chemical and physical structure of the soil. Using native plants is optimal when possible. The climate can change with trees, which will cool the area - In a model if you remove trees you decrease precipitation and increase temperatures. Trees affect the climate in many aspects, through immediate cooling effects as well as long term CO2 sequestration, which reduces CO2 in the atmosphere.

26

coolnessallday t1_j1unze7 wrote

Wow...I'm impressed. There are a host of reasons for your work and we all applaud you. I've been involved in food security for some time as well and have been lecturing on an informal basis in all my travels, the need for better understanding and applications in phenology. Mother nature is not altruistic, but gives off life allowing sustainability for those who adapt. Shalom to you.

11

Wrong_Swordfish t1_j1uom0g wrote

How does human interaction (e.g. walking in the desert) affect the outcomes of plant growth in the desert?

8

IsraelinSF t1_j1vdko6 wrote

Humans and plants have a mutual effect on each other. Just walking in the desert could have direct effects such as changes in soil structure and germination, as well as indirect effects in the rhizosphere. Anything from walking to building to the use of cars can have these effects.

10

bornswift t1_j1utzwo wrote

Are there any known attempts to genetically engineer plants or fungi to grow in deserts to help reverse desertification?

6

IsraelinSF t1_j1vjbwr wrote

Yes, there are many attempts to genetically engineer plants in this way. Today, the science is moving to Crisp R, which is gene editing involving targeted mutations. The attempts are very diverse, and success until now has been relatively small. The main attempts are in trying to create plants that are water-use efficient, as explained in my response about C4 plants, and that are high-temperature tolerant. There are also attempts using conventional breeding. In my opinion, what we call Crisp R or GMO is the same as using breeding. It is just a fast way of breeding that needs to be done carefully, but it is necessary in a changing environment. With conventional breeding, every plant or fruit we eat today has been modified. In my opinion, GMO relates to all food we eat today, so whether we do it faster or slower has no effect, but it must be done in a careful and controlled way.

9

RavenousOwlhead t1_j1ua43o wrote

Are there any unique plants other than cacti found in the deserts? It may sound stupid but I am no plant expert but I am curious.

5

IsraelinSF t1_j1vg5mt wrote

In the desert you will find a large variety of plants from annuals to perennials to flowers and many others - cacti are just one example. In deserts in Israel, cacti are a minority. Plants can be divided into three categories. The most common are C3 plants, which make up 85% of species and biomass. The rest of the species can be categorised into two groups: C4 plants and CAM plants. C3 plants get their name because the carbon product produced is a three carbon product. Similarly, C4 are called that because they produce a four carbon product. CAM is an acronym for crassulaceae acid metabolism. C4 and CAM plants are considered to be more tolerant to arid conditions such as drought, salinity, and high temperatures. Cacti are just one group of CAM plants. Plants in general when they open their stomata to absorb CO2 they lose water. CAM plants open their stomata at night, thereby minimising water loss. In C4 plants the enzyme that first takes in CO2 from the atmosphere is more efficient and therefore the time that the stomata opens can be shortened. . An example of C4 plants in maize, or corn. There are also many C3 plants that have specific adaptations, from being an annual that only grows for a short time when there is rain, to being very tolerant to salinity, nutrition deprivation, high light, and many other such adaptations. Other adaptations include unique symbiosis with the rhizosphere and other organisms. One annual plant in the Negev, called Salsola Inermis, was the first plant I studied as a researcher in the Negev. The uniqueness of this plant is that it is a summer annual desert plant, meaning it grows in summer months when there is no rain at all. It germinates at the end of March when there is minimal rain then grows to maturity in the summer, in an area that is very deprived of nitrogen. Two main factors for the plants in the desert is lack of water and nitrogen, making this plant special. With UC Berkeley we managed to find for the first time that this species uses water from dew. They distinguish dew from other water through the different chemical characteristics of hydrogen and oxygen in water. In addition, we found a unique three-way symbiosis between Salsola Inermis, weevils, and nitrogen fixing bacteria that live in the guts of the weevil. We showed that the weevils contribute nitrogen to the Salsola Inermis which they get from the bacteria, and the Salsola Inermis contributes sugars to the weevils in addition to water from the dew. All three organisms benefit.

22

hari2897 t1_j1u4v8g wrote

If an area that was once extremely fertile becomes deserted and loses all its flora and fauna , will the plants that ever grow there later be something similar to cactus ? How did plants like Cactus 🌵 get into deserts ? Is it due to millions of years of evolution in that specific area ? I'm supposing , for something like cactus to evolve , that area should have been a desert for millions and millions of years such that there was enough time for something like cactus to evolve. So what happens due to our deforestation? How long before things spring back ?

4

IsraelinSF t1_j1vjrz5 wrote

The plants that grow back may be similar to cacti, but many plants with many adaptations can exist in the desert. See CAM, C4, and C3 plants above. Deforestation enhances desertification. How long it takes for things to spring back depends on many factors, so it cannot easily be predicted.

3

darthvirgin t1_j1ue5tm wrote

What’s the most interesting or impressive adaptation of dessert plants, or one that’s particularly unique?

4

IsraelinSF t1_j1vgfmz wrote

Here is an example from one of our previous responses: One annual plant in the Negev, called Salsola Inermis, was the first plant I studied as a researcher in the Negev. The uniqueness of this plant is that it is a summer annual desert plant, meaning it grows in summer months when there is no rain at all. It germinates at the end of March when there is minimal rain then grows to maturity in the summer, in an area that is very deprived of nitrogen. Two main factors for the plants in the desert is lack of water and nitrogen, making this plant special. With UC Berkeley we managed to find for the first time that this species uses water from dew. They distinguish dew from other water through the different chemical characteristics of hydrogen and oxygen in water. In addition, we found a unique three-way symbiosis between Salsola Inermis, weevils, and nitrogen fixing bacteria that live in the guts of the weevil. We showed that the weevils contribute nitrogen to the Salsola Inermis which they get from the bacteria, and the Salsola Inermis contributes sugars to the weevils in addition to water from the dew. All three organisms benefit.

11

iSoinic t1_j1ul7o6 wrote

More efficient watering systems are needed in deserts/ arid regions. Many regions in the world are facing a net loss of water amount, becoming more arid and are about to face vegetation zone shifts.

Which general adaptations can you recommend to farmers all over the world, who will be challenged by this? Are there ways to "reform" their way of working, e.g. saving their traditional knowledge and keep going with some adaptations (e.g. more heat resistant crops, different watering techniques), or will there be more severe transformations needed (completely new crops, far less irrigated area, changes of intensity and soil usage)?

How well is this accepted in the agricultural bubbles you have encountered as a scientist? Are those people likely to make those necessary adaptations, or will they wait for too long, ultimately giving other market participants, who are focussing on sustainability in the first place, a better market potential?

4

IsraelinSF t1_j1vhsmg wrote

One great method is drip irrigation. These days we can even go further, and say drip fertigation, which is the combination of irrigation and fertilizer. Drip fertigation is spoon-feeding an individual plant and can be used to minimize water loss and fertilizer contamination of the soil. In addition, in many areas the soil can be too harsh to grow plants, and in such cases we can grow the plants in a detached platform. This enables us to control exactly what is given to the plants without contaminating the soil. In general, we need to do three things. The first is agrotechnology, such as drip irrigation and the platform. The second is genetics - using species and cultivars that are efficient in their water and nutrient use. The third is recruiting the knowledge that has been gathered over the past 20 to 40 years in arid regions.

We work closely with farmers in order to maintain economic agriculture which is also sustainable in the desert.

12

Calecog t1_j1uop58 wrote

Well...how do you grow plants in the deserts?

4

IsraelinSF t1_j1vhv37 wrote

Water, nutrients, sunlight, and lots of love.

11

BarberOk271 t1_j1ueqiy wrote

What's the basic cellular difference between plants grown in the desert compared to other regions?

3

IsraelinSF t1_j1vgo9c wrote

Plants in the desert are similar to others. There is a large variety in the desert, all different in their mechanisms. Many desert plants are C4 and CAM plants. CAM is an acronym for crassulaceae acid metabolism. C4 and CAM plants are considered to be more tolerant to arid conditions such as drought, salinity, and high temperatures. Cacti are just one group of CAM plants. Plants in general when they open their stomata to absorb CO2 they lose water. CAM plants open their stomata at night, thereby minimising water loss. In C4 plants the enzyme that first takes in CO2 from the atmosphere is more efficient and therefore the time that the stomata opens can be shortened. . An example of C4 plants in maize, or corn. There are also many C3 plants that have specific adaptations, from being an annual that only grows for a short time when there is rain, to being very tolerant to salinity, nutrition deprivation, high light, and many other such adaptations.

2

TeeTaylor t1_j1up9i7 wrote

Do plants absorb different minerals depending on what kind of soil they are in? If so, do they have a way of regulating how much of a particular mineral they absorb? I'd imagine desert soil is higher in certain minerals than, say, volcanic soil or mountain soil.

I know commercial fertilizers use the the NPK ratio, but how do desert plants regulate that ratio internally?

3

IsraelinSF t1_j1vibi6 wrote

Plants absorb different nutrients depending on the chemical and physical composition of the soil. Desert soils are usually lower in all nutrients, and therefore desert plants are usually efficient in their nutrient use. Measuring the nutrient use is a very important tool for sustainable agriculture, and is at the forefront of today’s research. We can measure online in order to provide the farmer with accurate data, so he can use exact amounts of nutrients. This creates a sustainable practice - maximizing yield with minimal waste. Nutrients can be absorbed, assimilated, or stored depending on the specifics of the species and the conditions.

7

Ironhyde36 t1_j1us723 wrote

Was wondering if you got to check out the cacti that grow up here in the mountains an hills in Montana. We have a cacti that grows across the ground up here. It survives the harsh winters up here and I was curious why it lives but other cacti die. They freeze then when they thaw out they turn to mush but the Montana cacti that grows higher and colder on the mountains live?

3

IsraelinSF t1_j1vin6n wrote

I have not studied specifically the cacti in Montana. The adaptations that enable cacti to grow in the desert are the same that enable them to grow in extreme cold. The common factor between extreme cold and desert is drought. In the desert there is less water, and in freezing areas there is less water in liquid-form. The cacti are part of the CAM plant family, which open their stomata at night, thereby minimising water loss.

4

YoungLadHuckleberry t1_j1v5iq7 wrote

Would you say research positions like yours are commonly accessible for PhD graduates of plant sciences and other similar biology related degrees or would you consider yourself rather lucky to have gotten the spot? I‘m also studying for a B.Sc. in Biology however I‘m a bit unsure about the job opportunities afterwards.

3

IsraelinSF t1_j1vlesw wrote

Research positions are accessible both in industry and in academics. In Israel the academics is relatively limited, but you can find positions worldwide. From my experience, my students (I have had over 50) have found positions in agrotech and biotech industries. As long as you’re doing what you love, you will find something worthwhile.

3

hey-look-over-there t1_j1uaejj wrote

What's some tasty plants I can grow in Nevada or Arizona desert/drought? Also would it be possible to grow agave (for tequila and syrup) industrially in desert regions?

2

IsraelinSF t1_j1vjwwt wrote

There are many options for growing plants, from dates to prickly pear to marula.

3

delliejonut t1_j1urz5h wrote

Hi! Going to check out your link in a moment but first, a question off the top of my head.

There's a wide array of dry climates on earth. The American Southwest, Death Valley, the Sahara, Gobi desert, Patagonia, Karakum ect. Is there overlap between the plant mechanisms you study in these different environments, or do plants in hot/cold environments and different locations adapt in unique ways?

2

IsraelinSF t1_j1vklr5 wrote

Desert and cold environments are similar in that they both lack available water. The desert lacks water and colder environments lack water in liquid form. So the plants adapt similarly.

5

Mabunnie t1_j1vczdn wrote

You are doing great work. Here's a silly one! =)

Which is your favorite plant in your study area to pet? What is the texture like?

2

Captainzabu t1_j1vh77k wrote

Greetings. I just want to know what staple crop is the best suited for arid/dry climates?

2

IsraelinSF t1_j1vmxx2 wrote

There are many desert plants that are rich in unique biochemical compounds that can be used for the pharmaceutical and cosmetic industries. For example, the Commiphora Gileadensis, that was mentioned in the Bible, has sap that can be used as an important essence for perfume. We have found specific anti-cancerous effects in the sap as well, for three different types of cancer.

6

SalmonHustlerTerry t1_j1uk20b wrote

Do you have to introduce new soil when first planting in desert areas, or is the sand sufficient enough for roots to take hold?

Also do you have to constantly feed the plants nutrients? Or is there enough in ground?

And how long would it take, or how much desert would have to be reclaimed for a decent mycelium network to be established for the plants to pass nutrients around for themselves?

1

IsraelinSF t1_j1vkb6r wrote

It all depends on which desert. In many cases if you want intense agriculture it is better to use a detached platform. It also depends on the species. Some species such as date palms can be grown directly in the soil. Feeding with nutrients is important but you can also put legumes between rows of crops that will help enrich the soil with nitrogen and other nutrients, since legumes are symbiotic with bacteria that fix nitrogen from the atmosphere.

In regards to mycelium, it depends on the fungi species and the specifics of the soil and climate.

3

Western_Hostility t1_j1uttk6 wrote

In the Chihuahuan Desert, there is a shift from grasslands to more woody plant species. Do you think it's possible to go back to the grasslands or at least some hybrid state that provides some production for wildlife or commercial grazing?

1

IsraelinSF t1_j1vkqzj wrote

It is possible but I am not sure it is recommended from an ecological perspective.

2

Reditate t1_j1uz23r wrote

Explain The Tree of Ténéré to me.

1

IsraelinSF t1_j1vkz2a wrote

It is an acacia tree. In Israel it lives in the harsh desert, the northernmost place in the world where it appears. There are three species of acacia in Israel.

2

TheGnarWall t1_j1v19pd wrote

Do desert plants have the ability to use stored carbon when prolonged drought conditions prevent them from photosynthesizing? And if so, do desert areas change from being sinks of CO2 into being sources of CO2?

1

IsraelinSF t1_j1vl5fm wrote

Desert plants, like all plants, can use storage compounds but without photosynthesizing they will not continue to grow. Many plants can change from sinks to sources of CO2 depending on their physiological state. This is not specific to desert plants, but rather all plants.

2

JennaSais t1_j1v7ftp wrote

When growing plants in the desert for agricultural purposes, it seems the water you would need to grow them well would be a major concern. Are these plants being bioengineered to require less water, primarily? What about the nutrition the plant needs? How are those needs being addressed and what challenges are particular to the desert environment vs. an environment with loamy soil?

1

IsraelinSF t1_j1vlumg wrote

Water is a big concern for desert plants. The challenges they encounter include lack of water and nutrients, but also high temperatures. This is addressed in three manners: agrotech, genetics of the crop, and knowledge that has been gathered over years. Plants won’t grow without water, so water-use efficiency is crucial. However, some plants require a lot of water. One glass of wine needs 40L of water. One date needs 20 to 40L. In Israel today with desalination and intelligent water use, lack of water is no longer a big problem, but we still must think about these factors. These are challenges we face and think about on a daily basis.

1

coilycat t1_j1v9n3v wrote

Have you encountered folks researching vegan regenerative agriculture? I know of people who are able to farm without using animals, but I've never heard of it in drylands. To be honest, I don't know where animal inputs are used in deserts in the first place, since I expect that grazing would increase desertification.

1

PeanutSalsa t1_j1vecd9 wrote

What fruits and vegetables can and can't grow in the desert?

1

IsraelinSF t1_j1vm4o7 wrote

Almost all fruits and vegetables can be grown, if you are not looking for profit.

2

IsraelinSF t1_j1vm62r wrote

Almost all fruits and vegetables can be grown, if you are not looking for profit.

1

GenocidalGenie t1_j1vgzci wrote

I've heard about people using biosolids from waste treatment when attempting to amend deserts - what's your take on this? Does it help at all?

1

IsraelinSF t1_j1vmctm wrote

Biosolids can help, but we have to do it in a controlled way using experience, knowledge, and specific soil crops and climate.

1

PeanutSalsa t1_j1vzamc wrote

Is it possible that at some point through the use of technological and agricultural advancements, desert soil can become as fertile and economical to grow crops in as traditional soil?

1

failingtoremember t1_j1w02hf wrote

What do you think about chinas plan for a green desert?

1

ProfXavier89 t1_j1wmuvh wrote

In your opinion, could we make arrakis a waterworld?

1

purpleyuan t1_j1wnhwp wrote

It's my understanding (as a layperson) that a great deal of environmental issues around agriculture are around water management. Is one of the goals of your research to create hardier crops that might reduce the need to irrigate constantly, which drains our lakes and rivers (among other environmental impacts)?

1

UndercoverDoll49 t1_j1wtzh4 wrote

I got a stupid question but I'd chasticise myself if I don't ask it

In the game My Time At Sandrock, the characters use an "algae paste" to prepare desert soil for planting larger plants. Is this based on a real technique or proposed technique?

1