For all living been need energy for their metabolism. The metabolism is include with all the vital activities happening in the body and it need energy supply continually When a leaf detached and keep in a sugar solution, it will enhance the respiration and it will act as row material for the metabolic activities,this is the reason, when we add a sugar solution to a vital tissue it will live longer . this is the concept behind techniques in tissue culture, the phenomena is correct and if we add glucose sugar and other micro nutrient to the media in correct amount you can keep the plant leaf strip longer.

When we keep leaf strip in sugar solution due to viscosity of the sugar and it stickiness it will block transpiration activity of the leaf by blocking stomata of leaf in both sides.(the solution act as sealing material) If transpiration low , the leaf strip not wilt and the leaf keep as fresh tissue, and the leaf could be keep longer.

The leaf blade of a dicot can be cut under dilute EDTA and a portion with main vein fed with chemical that are trasnported inside by transpiration while the rest of leaf is still attached, but as far i know sugars are relased and not uptaken. An alternative is pulse chase with 14 or 13CO2. What for is a big question to go on with this lab. King et al. Plant Physiology January 1974 vol. 53 no. 1 96-103

Thank you weerasuriyage! Can I spray sugar solution on leaf? I want to feed sugar on natural living leaf, rather detach leaf.

Thank you Guido. I want to feed sugar on natural living leaf. If the sugar can not be uptaken, I can't achieve my goal. That's terribile.

Intact leaves of many plants are not permeable by solutes or they will die immediately in low humidity in case they could exchange water directly. In fact water and inorganic nutrients are taken by roots and sugars are made by photosynthesis and transported to roots: the stomata exchange gases or vapours and the suction pump of evaporation maintains the plant alive. Some aphid or fungus can make permeable the lef walls in order to take sugars out of it, but you would like to produce the opposite way. We now already that build up of sugars in leaves feeds back photosynthesis and blocks it, as appens in low temperature. Mosses and lychens or algae are possible choices for sugar import. In succulent plants like Kalankoe spp you can directly inject a solution in leaf blades parenchima with a small syringe. One leaf can take up 6 ml. In vitro is a sort of heterotrophy too, but just in proliferation, without roots. At end the only way in the rest of plants is not very wise, is just cutting the leaf end, using EDTA 1mM for maintaining the vessels open and feeding a 0.5M sugar through the cut with a water soluble dye to check diffusion. At least you got half leaf alive and possibly it will last some day.

Some time ago we used a sort of infiltration technique to apply bacteria and some chemicals to intact leaves. The technique involves applying a vacuum to leaf with a syringe without a needle. You need to take up some amount of solution into it (no more than half of volume), then press gently the tip of syringe to leaf surface and gently apply vacuum by pulling a plunger. After that, by releasing the plunger, solution moves inside the leaf.

And of course, you need to apply water in a same way for control plants

Hi Gederts! Can you tell me more details about the infiltration technique?

Hi Wanzhuo! I am afraid that there is no more detailed description available. You can search plant pathology papers in Scholar Google by "bacteria" "infiltration" "leaf" "syringe" for appropriate references. Basically, what you achieve by this method, is infiltration of a certain amount of solution inside intercellular space (apoplast) within some area of leaf (10 mm in diameter?). I suggest you just need to start experimenting with your model plant and water, to adjust force, amount of liquid etc. Better use realtively small plastic syringe (1-2 mL) because there is a caution not to perform much mechanical damage to leaf.

Dear Wanzhuo I wrote my comment on train and try now to be more precise in spelling and logic: the first question, quite unattended, is: What for?

If you have a strong but unresolved motivation you can choose

-push pull with a syringe (Gederts and check infiltration as in Beyslag & Pfantz Planta)

-inject in succulent leaf parenchima like in Kalanchoe for flower induction,

-use algae or lychens

Dear Mr. Bongi. I'm sorry for my English. In fact, I want to see the effect of sugar feeding on leaf cell wall synthesis. At first, I want to spray or dip sugar (sucrose/glucose) solution on intact leaves of C3 plants, rather the detached leaves. I think using intact leaves as materials m are more real in natural environment. But now, I know sugar are less likely to be uptaken from exogeneous feeding. So maybe injection might be a better choice. But injection technique can not be applied in crop production.

Wanzhuo, since you hope to keep the leaves intact, the best way to increase sugar levels in these leaves is to use localised CO2 enrichment techniques to the few specific leaves. High CO2 given to the leaves in the presence of suitable light will boost leaf photosynthesis and thereby increasing the leaf carbohydrate levels. The selected leaves can by bagged using transparent ziploc bags (read page 304 of the book chapter) or specially constructure perspex/plastic chambers. What do you think?

I want to see the effect of sugar feeding on leaves which had acclimated to longterm insufficient photosynthetic products under specific condition such as low light and low CO2. Would CO2 enrichment influence other physiological traits? I think so. That's would be harder to explain the effect of sugar feeding.