Re-watering: An effective measure to recover growth and photosynthetic characteristics in salt-stressed Brassica napus L.

Abstract

Salinity is one of major environmental problem which is limiting the agricultural production. This research was conducted to evaluate the effect of re-watering on Brassica napus L., and determination of an appropriate regime for dilution of salted water by studying photosynthetic and growth response of B. napus to salt stress and subsequent re-watering. Plants were treated with NaCl (Nc 1 : 2.5, Nc 2 : 5, Nc 3 : 10; g L -1 ); Na 2 SO 4 (Ns 1 : 2.5, Ns 2 : 5, Ns 3 : 10; g L -1 ) and mixed salts treatments (M 1 : Nc 1 + Ns 3 ; M 2 : Nc 3 + Ns 1 ; M 3 : Nc 2 + Ns 2 ; g L -1 ) and 0 as control, followed by re-watering. In salt stress phase, maximum reduction in net photosynthetic rate (P N ) was noted 79.54%, 80.72%, 84.54%, and 74.84% for Nc 3 , Ns 3 , M 1 and M 2 , respectively, under high concentration levels. To maintain P N , carbonic anhydrase (CA) activity was stimulated and kept water status stable under low (Nc 1 and Ns 1 ) to medium concentration levels (Nc 2 , Ns 2 and M 3 ), and the decreases in P N under Nc 2 , Ns 2 and M 3 were 48.28%, 55.58% and 58.69%, respectively. However, during rewatering phase, growth and physiological parameters were recovered well due to regulation of CA activity under low to medium concentration levels. Relatively as compare to other stress levels more recovery in P N was found after rewatering under medium concentration levels, which were 44.94%, 53.45% and 63.04%, respectively. Though aimed at consideration of high production in B. napus, the best re-watering time was found to be when plants undergo medium concentration levels. Therefore, this study provides a new method for dilution of saline irrigation based on plant physiology.

New sight: rapid monitor of intracellular water information in plant leaves based on electrophysiological parameters

“…The abiotic or biotic stimulus including drought, salt stimulation, cold stimulation, diseases and insect pests etc. can trigger various electrical activities of plants [10,11,22,23]. Meanwhile, these stimulu can also cause changes of intracellular water status in plant leaves.…”

“…However, this method is instability, difficult to manipulate and low authenticity, and the plant electrical signals lacks representativeness, reproducibility and comparability due to needling injury can directly change the electrical signals, as well as different environment, measuring people and other factors [17,30]. Moreover, the intracellular water transportation, water-holding and utilization information in plant leaves can't be obtained by simple C, Z and Xc of electrical signals [9][10][11]31]. In addition, the water information in plant leaves obtained by photosynthesis-transpiration, turgor pressure, water potential, spectrometry, stable oxygen and hydrogen isotope, and other methods still can't directly reflect the intracellular water information [1,[6][7][8].…”

“…However, the leaf water contents can't directly reflect the dynamic information of intracellular water in plant leaves, and the limitations of such methods in terms of on-field, price, complex or accuracy have limited to their application in situ. Recently, plant electrophysiological information has been applied to study water information of plants [9][10][11][12][13][14]. For instance, Javed et al [11] evaluated irrigation effects using diluted salted water based on electrophysiological properties.…”

“…Recently, plant electrophysiological information has been applied to study water information of plants [9][10][11][12][13][14]. For instance, Javed et al [11] evaluated irrigation effects using diluted salted water based on electrophysiological properties. Zhang et al [12] demonstrated electrophysiological properties of the plants reflecting their ability to resist drought and defined leaf tensity to represent plant drought resistance.…”

A Plant’s Electrical Parameters Indicate Its Physiological State: A Study of Intracellular Water Metabolism

“…Can these intrinsic relationships be described by corresponding physical mechanism models? The impedance and capacitance values of plants have always been used to evaluate the water status, maturity and growth of plants [ 13 , 14 , 15 , 16 , 17 , 18 ]. Moreover, mesophyll cells have long been regarded as concentric sphere capacitor with both inductor and resistor functions, due to their specific composition and structure [ 19 , 20 ].…”